Re: [PATCH v6 3/4] PCI: dwc: Skip PME_Turn_Off message if there is no endpoint connected
From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2025-09-24 19:59:57
Also in:
imx, linux-pci, lkml, stable
On Wed, Sep 24, 2025 at 03:23:23PM +0800, Richard Zhu wrote:
A chip freeze is observed on i.MX7D when PCIe RC kicks off the PM_PME message and no any devices are connected on the port.
s/no any/no/
To workaroud such kind of issue, skip PME_Turn_Off message if there is no endpoint connected.
s/workaroud/work around/
quoted hunk ↗ jump to hunk
Cc: stable@vger.kernel.org Fixes: 4774faf854f5 ("PCI: dwc: Implement generic suspend/resume functionality") Fixes: a528d1a72597 ("PCI: imx6: Use DWC common suspend resume method") Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com> Reviewed-by: Frank Li <Frank.Li@nxp.com> --- drivers/pci/controller/dwc/pcie-designware-host.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c index 57a1ba08c427..b303a74b0fd7 100644 --- a/drivers/pci/controller/dwc/pcie-designware-host.c +++ b/drivers/pci/controller/dwc/pcie-designware-host.c@@ -1008,12 +1008,15 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci) u32 val; int ret; - if (pci->pp.ops->pme_turn_off) { - pci->pp.ops->pme_turn_off(&pci->pp); - } else { - ret = dw_pcie_pme_turn_off(pci); - if (ret) - return ret; + /* Skip PME_Turn_Off message if there is no endpoint connected */ + if (dw_pcie_get_ltssm(pci) > DW_PCIE_LTSSM_DETECT_WAIT) {
This looks racy and it sounds like this is a workaround for an i.MX7D defect. Should it be some kind of quirk just for i.MX7D?
+ if (pci->pp.ops->pme_turn_off) {
+ pci->pp.ops->pme_turn_off(&pci->pp);
+ } else {
+ ret = dw_pcie_pme_turn_off(pci);
+ if (ret)
+ return ret;
+ }
}
if (dwc_quirk(pci, QUIRK_NOL2POLL_IN_PM)) {
--
2.37.1